There are known position measuring apparatuses for measuring the three-dimensional position of an object using images obtained from cameras. Such a position measuring apparatus is based on a camera model, i.e. a single-focal cameral model, configured such that light enters each camera while focusing on the center of the lens of the corresponding camera.
The measurement accuracy of such a position measuring apparatus based on the single-focal camera model may greatly decrease if an object is placed between each camera and a target subject, for example, if each in-vehicle camera captures a target subject through the front windshield.
In contrast, Japanese Patent Application Publication No. 2012-75060, which will be referred to as a published document, discloses a non-single-focal camera model describing a non-linear map in place of the single-focal camera model describing a linear map.